Endocrine

Question 1

pituitary apoplexy-what is it, presentations, and treatment

Answer 1

acute hemorrhage into the pituitary gland

• associated with preexisting pituitary adenoma
• severe headache, cranial nerve involvement (bitemporal hemianopsia, ophthalmoplegia), meningeal irritation
• treat with glucocorticoid replacement (prevent life-threatening hypotention) or surgical decompression

Question 2

Kallmann syndrome-what is it

Answer 2

absence of GnRH secretory neuronsin the hypothalamus due to defective migration form the olfactory placoid

-associated with mutatio nin the KAL-1 gene or fibroblast growth factor receptor-1gene

–> central hypogonadism and anosmia, delayed puberty

Question 3

mutation in what gene is associated with medullary thyroid cancer

Answer 3

RET proto-oncogene

Question 4

what are the 3 P’s of MEN1

Answer 4

parathyroid adenomas, pituitary tumors, and pancreatic endocrine tumors

Question 5

how can patients still metabolize fructose when fructokinase is deficient

Answer 5

hexokinase takes over fructose metabolism

Question 6

what can and can’t use ketones for energy

Answer 6

can: brain, kidneys, cardiac muslce and skeletal muscle

can’t: erythrocytes b/c lack mitochondria

ketones produced int eh liver

Question 7

how can ethanol cause hypoglycemia

Answer 7

by inhibiting gluconeogensis

Question 8

clinical manifestations of congenital hypothyroidism

Answer 8

normal at birth
-lethargy, enlarged fontanelle, protruding tongue, umbilical hernia, poor feeding, constipation, dry skin, jaundice

-6 P’s: pot-bellied, pale, puffy-faced, protruding umbilicus, protuberant tongue, poor brain development

Question 9

growth hormone stimulate release of insulin-like growth factor-1 (IGF-1) from what organ?

Answer 9

liver

Question 10

how come you don’t see high urinary excretion of ketones with type 2 diabetes

Answer 10

high total insulin levels suppress ketone formation

Question 11

mechanism of beta-blockers for thyrotoxicosis (thyroid storm)

Answer 11

decreases peripheral conversion of T4 to T3 by inhibiting iodothyronine deiodinase

Question 12

presentation of urea cycle disorders

Answer 12

vomiting, tachypnea, and confusion/coma secondary to hyperammonemia

most common disorder: ornithine transcarbamylase deficiency–> elevated urinary orotic acid

Question 13

avidin in egg whites binds to ______

Answer 13

biotin (vitamin B6)–> deficiency in biotin leads to dermatitis, alopecia, changes in mental status, myalgias, anorexia, and lactic acidosis

Question 14

essential amino acid in phenylketonuria

Answer 14

Tyrosine–> cannot be synthesized from phenylalnine due to deficiency of phenylalanine hydroxylase so can’t convert phenylalanine to tyrosine

Question 15

most common complication of statin

Answer 15

myopathy

Question 16

how can glucocorticoids lead to hyperglycemia

Answer 16

increase hepatic gluconeogenesis and glycogenesis along with peripheral antagonism of insulin

Question 17

mechanism of action of Finasteride

Answer 17

5-alpha-reductase inhibitor that suppresses periperal conversion of testosterone to dihydrotestosterone

used for treatment of benign prostatic hyperplasia and androgenetic alopecia (increased in 5-alpha-reductase is associated with androgenetic alopecia)

Question 18

3 primary effects of PTH

Answer 18

• increase osteoclastic bone resorption–> increase calcium and phosphate release into the circulation
• increase renal calcium reabsorption and reduces phosphate reabsorption (excrete phosphate but keep calcium)
• increased formation of active vitamin D, which increases intestinal calcium and phosphate absorptioin

Question 19

what is neurophysin

Answer 19

carrier protein for oxytocin and vasopressin (ADH), hormones produced within the paraventricular and supraoptic nuclei, respectively, and released from the posterior pituitary

-point mutation in neurophysin II lead to hereditary hypothalamic diabetes insipidus

Question 20

how can estrogen increase total T4

Answer 20

estrogen raises circulating thyroxine-binding globulin –> reduce free T4 and free T3

–> increase in thyroid hormone production

Question 21

side effect of niacin

Answer 21

-decrease renal excretion of uric acid leads to acute gouty arthritis, flushing, hyperglycemia, and hepatotoxicity

use to decrease hepatic synthesis of triglycerides and VLDL and reduces clearance of HDL

Question 22

mechanism of action for meglitinides

Answer 22

short-acting glucose-lowering medication

close ATP-dependent K+channel in the pancreatic beta cell membrane, inducing depolarization and stimulating insulin release

Question 23

mechanism of action for SGLT2 inhibitors

Answer 23

oral anti-diabetic

• decrease proximal tubular reabsorption of glucose to promote urinary glucose loss
• should be avoided in those with moderate-to-severe renal impairment

Question 24

side effect of thioamides (propylthiouracil, methimazole)

Answer 24

skin rash, agranulocytosis (rare), aplastic anemia, hepatotoxicity

methimazole=teratogen

Question 25

2 signs of hypocalcemia associated with hypoparathyroidism

Answer 25

Chvostek sign: facial muscle contraction elicited by tapping on the facial nerve anterior to the ear trousseau sign: carpopedal spasm triggered by prolonged inflation of a blood pressure cuff around arm

Question 26

what organelle is found in all steroid-producing cells (eg, cells in the adrenals, gonads, and liver)

Answer 26

smooth ER

Question 27

mechanism of actions of sulfonylureas (eg, glyburide)

Answer 27

increase insulin secretion rate of residual pancreatic islet beta-cells and reduce blood glucose levels in patients with type 2 diabetes mellitus --> increase circulating C-peptide

Question 28

mechanism action of Leuprolide

Answer 28

GnRH analog to suppress testosterone levels in treatment of prostate cancer pulsatile fashion--> agonist properties continuous fashion--> downregulation of GnRH receptors on gonadotropin cells in the pituitary gland

Question 29

what is Hartnup disease

Answer 29

autosomal recessive metabolic disorder due to inactivating mutations affecting the neutral amino acid transporter (esp. tryptophan), in small intestine and proximal tubule of kidney --> need tryptophan to get niacin so patient has niacin deficiency

Question 30

which glucose transport proteins (GLUTs) is the only one that is responsive to insulin?

Answer 30

GLUT4 (skeletal muscle cells and adipocytes) the other ones are insulin-independent

Question 31

complications of familial chylomicronemia syndrome?

Answer 31

recurrent episodes of acute pancreatitis, lipemia retinalis (milky-appearing retinal vasculature), and eruptive xanthomas syndrome- auto recessive with lipoprotein lipase (LPL) deficiency so can't clear dietary lipid loads (esp. chylomicrons)

Question 32

how does the calcium levels regulate the secretion of parathyroid hormone (PTH)

Answer 32

through calcium-sensing receptors= transmembrane G-protein-coupled (metabotropic) receptors that help to regulate the secretion of parathyroid hormone (PTH) in response to changes in circulating calcium levels

Question 33

histological finding of medullary thyroid cancer

Answer 33

nests or sheets of polygonal or spindle-shaped cells with extracellular amyloid deposits derived from calcitonin

Question 34

alpha-2 adrenergic receptors _____ insulin secretion, and beta-2 adrenergic receptors ________ insulin secretion

Answer 34

inhibit; stimulate

Question 35

what are the acute effects of corticosteroids on the white blood cell count

Answer 35

increased neutrophil count ("demargination" of neutrophils previously attached to vessel wall) decreased lymphocyte, monocyte, basophil, and eosinophil counts

Question 36

characteristic of Klinefelter syndrome

Answer 36

primary hypogonadism (elevated FSH and LH, low testosterone); long lower extremities; small, firm testes; and azoospermia

Question 37

methimazole vs. propylthiouracil (PTU)

Answer 37

both are antithyroid drugs used to decrease thyroid hormone production methimazole preferred due to hepatotoxicity of PTU methimazole is teratogenic so PTU is preferred in the first trimester of pregnancy

Question 38

complications of subclinical hyperthyroidism

Answer 38

hypertension, accelerated bone resorption, and atrial fibrillation can also be caused by medications like levothyroxine

Question 39

prolactin production is stimulated by

Answer 39

TRH in patients with primary hypothyroidism, the increased production of TRH by the hypothalamus can lead to hyperprolactinemia